The known sampling devices in facilities for processing irradiated nuclear fuels use a combination of closed sample vessel and hollow needle filling to transfer the test solution into specimen flasks. The filling aperture of the sample vessel is in this case closed by a rubber septum which can be pierced by one or two hollow needles ground to an acute angle. Through these inserted hollow needles, the sample vessels are filled from a diverted component quantity of the pumped sample fluid.
U.S. Pat. No. 4,653,333 discloses a sampling device for radioactive and/or toxic substances. With this device, a sample vessel is filled by means of a pipe system through a single needle head within a shielded space. The hollow needle of the needle head is fixed in the axis of a rotary body having an end face facing toward the interior of the housing. This end face has a conical recess which tapers down to the needle diameter. At the end of the rotary body there is a feed chamber in the housing of the sampling device and the feed chamber is connected to a feed line. A return line is connected to the lowest point of the feed chamber.
The needle head has only one hollow needle which centrally pierces the septum which seals the sample vessel and is thereby centrally guided in the septum. Thus, it is possible to insert a larger needle which has the advantage of a reduced tendency to clog and which is less readily bent.
The results obtained with this known sampling device were satisfactory. Further improvements are, however, sought for use with suspensions containing solids and in order to obtain as far as possible representative specimens.